It has been 23 years since the first human baby was born using in vitro fertilization. Since that time, advances in research to circumvent human infertility have expanded at a phenomenal rate. One of these advances is the recent success of ovary cryopreservation that, in turn, has created the need for complete oocyte development in vitro. The ability to efficient grow normal oocytes in culture, however, is still in the experimental stages. In addition, preliminary studies using the mouse indicate that adults derived from in vitro grown oocytes may have developmental abnormalities. The research being proposed here will use the mouse as a model system to determine if in vitro oocyte growth has negative consequences on offspring health. In addition, we will use this technology to define some of the mechanisms of normal oocyte development. This study will lead to a better understanding of oocyte development which, in turn, will improve the efficiency and lower the risks of using in vitro oocyte growth for assisted reproduction.